Location based services (LBS) have become increasingly popular and a considerable amount of research effort has been directed to developing indoor localization systems. Also, due to the rapid growth of smartphones, such localization systems adopt various techniques that use sensory capabilities provided by the smartphones. For example, crowd-sourced Wi-Fi-based localization systems utilize user input for radio frequency (RF) scene analysis and map construction. Such crowd-sourced localization systems require sufficient contributions from users to populate the signal map.